It is shown by a research that, components in the air, such as aqueous vapor and oxygen, etc., have a great influence on the life time of an OLED. The main reasons lie in the following two aspects: the metal that functions as the cathode, for example, silver, aluminium and magnesium, is generally active, and it tends to react with the aqueous vapor, oxygen and the like that penetrate thereinto, thus the cathode work function of the cathode of an OLED device will be influenced; and the aqueous vapor, oxygen and the like that penetrate thereinto will further react with the hole transport layer and the electron transport layer, thus it may cause the device to fail. Therefore, in order to prevent the aging and unstability of an organic photoelectric device, an OLED device needs to be packaged effectively.
With the rising of flexible OLEDs, a packaging technology for flexible OLEDs is put forward correspondingly. On one hand, the packaging technology requires that, for the package structure, the aqueous vapor permeability should be at least lower than 5×10−5 g/m2 d, and the oxygen permeability should be lower than 10−5 cm2/m2 d; on the other hand, it also requires that the package structure has flexibility and bendability, thus the traditional rigid package structure cannot meet the requirements.
At present, novel package materials and package structures represented by film package structures come into existence. The existing film package structure includes a film such as inorganic insulating film of SiOx or SiNx, etc. Although an inorganic insulating film has high water and oxygen resistance, the film surface thereof is rough and has “apertures”, so that ambient water and oxygen tend to invade thereinto via the “apertures”, thus the water and oxygen resistance of the film package structure is lowered. Moreover, the existing film package structure consists of organic films and inorganic insulating films that are physically set alternately. Since the two kinds of layers are connected physically, interlayer detachment or breakage may occur after the film package structure is bended for several times, and thus the flexible display device will be damaged devastatingly, or the service life of the display device will be influenced.
Therefore, it is an important topic for those skilled in the art that there needs to provide a display device, which can effectively prevent water and oxygen invasion, and a film package structure, which can improve the bending resistance of the film package structure.